question

Given that that error is battery/output over voltage on the solar chargers I would be inclined to suggest that either...

The over voltage threshold is too low, which seems unlikely as looking at mine, it doesn't appear to be editable. (Note I have a BYD BMS and DVCC on so my SS is in remote )

OR

More likely your batteries internal BMS's are shutting down causing the DC voltage to spike due to a rapid reduction in current. I don't actually know but I suspect that the charge control ramp in the SmartSolar is 'relatively' slow whilst its over voltage error will likely be quick.

Are you in float or bulk when it trips? bulk I assume.

I assume the batteries have an internal BMS, what are its settings/thresholds?

I grant you that 14.4 sounds correct, I have an Ultramax 12V 100AH LIFEPO4, series/parallel bank, which is 25.6, nominal, and that is set to 28.8 Bulk, 27.6 float, which seems to be working just fine.

My point is either the voltage is going high or the charger is tripping early, given that 'set low' doesn't seem to be an option.

Try dropping the bulk setting to 0.1V below highest voltage you have seen without a trip, if that fixes it you would have to conclude its a BMS disconnect issue I think.
You could also connect a data logger, or meter with peek hold, and watch the voltage when it trips.

Best of luck, it sounds a bit odd whatever it is.

Al

Hallo !!

Kann natürlich sein das das BMS der Batterien da irgendwie sich einmischt, wie es scheint hat das deaktivieren des Synchron laden irgendwie geholfen . Seit dem ist der Fehler nicht mehr wieder erschienen.

As far as I know Victron LiFePO4 12,8V batteries require 14,2V absorption voltage. Check the cell voltages, the BMS may disconnect the batteries for cell overvoltge. The error 38 is due to the fact that the MPPT charger remains without battery and has to short-circuit the PV array connected.